[#42344] [ruby-trunk - Feature #5964][Open] Make Symbols an Alternate Syntax for Strings — Tom Wardrop <tom@...>

23 messages 2012/02/03

[#42443] [ruby-trunk - Bug #5985][Open] miniruby skews "make benchmark" results — Eric Wong <normalperson@...>

21 messages 2012/02/08

[#42444] [ruby-trunk - Bug #5986][Open] Segmentation Fault — Luis Matta <levmatta@...>

16 messages 2012/02/08

[#42471] [ruby-trunk - Feature #5995][Open] calling io_advise_internal() in read_all() — Masaki Matsushita <glass.saga@...>

20 messages 2012/02/10

[#42560] [ruby-trunk - Bug #6011][Open] ruby-1.9.3-p0/lib/webrick/utils.rb:184: [BUG] Segmentation fault — Vit Ondruch <v.ondruch@...>

12 messages 2012/02/13

[#42579] [ruby-trunk - Bug #6012][Open] Proc#source_location also return the column — Roger Pack <rogerpack2005@...>

14 messages 2012/02/14

[#42685] [ruby-trunk - Bug #6036][Open] Test failures in Fedora Rawhide/17 — Bohuslav Kabrda <bkabrda@...>

14 messages 2012/02/16

[#42697] [ruby-trunk - Bug #6040][Open] Transcoding test failure: Big5 to UTF8 not defined (MinGW) — Luis Lavena <luislavena@...>

10 messages 2012/02/16

[#42813] [ruby-trunk - Feature #6065][Open] Allow Bignum marshalling/unmarshalling from C API — Martin Bosslet <Martin.Bosslet@...>

22 messages 2012/02/23

[#42815] [ruby-trunk - Bug #6066][Open] Fix "control may reach end of non-void function" warnings for clang — Eric Hodel <[email protected]>

15 messages 2012/02/23

[#42857] [ruby-trunk - Feature #6074][Open] Allow alias arguments to have a comma — Thomas Sawyer <transfire@...>

20 messages 2012/02/24

[#42891] [ruby-trunk - Feature #6083][Open] Hide a Bignum definition — Koichi Sasada <redmine@...>

23 messages 2012/02/25

[#42906] [ruby-trunk - Bug #6085][Open] Treatment of Wrong Number of Arguments — Marc-Andre Lafortune <ruby-core@...>

14 messages 2012/02/25

[#42949] [ruby-trunk - Bug #6089][Open] Test suite fails with OpenSSL 1.0.1 — Vit Ondruch <v.ondruch@...>

13 messages 2012/02/26

[ruby-core:42432] [ruby-trunk - Bug #5353] TLS v1.0 and less - Attack on CBC mode

From: Hiroshi Nakamura <nakahiro@...>
Date: 2012-02-08 06:10:52 UTC
List: ruby-core #42432
Issue #5353 has been updated by Hiroshi Nakamura.


Backported to ruby_1_8 and ruby_1_8_7 by r34485 and r34486 respectively.
----------------------------------------
Bug #5353: TLS v1.0 and less - Attack on CBC mode
https://bugs.ruby-lang.org/issues/5353

Author: Martin Bosslet
Status: Open
Priority: High
Assignee: 
Category: ext
Target version: 2.0.0
ruby -v: -


A well-known vulnerability of TLS v1.0 and earlier has recently gained some attention:

http://www.theregister.co.uk/2011/09/19/beast_exploits_paypal_ssl/

Although this has been known for a long time (http://www.openssl.org/~bodo/tls-cbc.txt),
and a fix for this has been provided, in reality most applications seem to be working with

SSL_OP_ALL

which is a flag that enables some bug workarounds that were considered harmless. 

We, too, use this in ossl_sslctx_s_alloc(VALUE klass) in ossl_ssl.c. Unfortunately, 
this flag also includes

SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS

which disables the fix for the "CBC vulnerability". Here is what a comment says 
about the flag (OpenSSL 1.0.0d)

    /* Disable SSL 3.0/TLS 1.0 CBC vulnerability workaround that was added
     * in OpenSSL 0.9.6d.  Usually (depending on the application protocol)
     * the workaround is not needed.  Unfortunately some broken SSL/TLS
     * implementations cannot handle it at all, which is why we include
     * it in SSL_OP_ALL. */

If I understand http://www.openssl.org/~bodo/tls-cbc.txt correctly, the most
notable implementation that does not play well with these empty fragments
was (is?) IE - I don't know how this has evolved over time, I would have to 
research further.

An easy fix for the situation would be to discard SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS,
but this would risk affecting existing installations.

What do you propose? Should we solve this before the 1.9.3 release? 

(PS: The actual attack and fix are outlined in 

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.61.5887&rep=rep1&type=pdf

The attack to be presented by Thai Duong and Juliano Rizzo at 

http://ekoparty.org/cronograma.php (caution: currently the site is victim to the "reddit effect")

is very likely to be based on what was already known and should therefore hopefully
require no further fixes.) 

 


-- 
http://bugs.ruby-lang.org/

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